Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 762)

L-force | PLC Designer
General Editors
760 DMS 4.1 EN 03/2011 TD29

Reset operator 'R=': The value will be "reset", that is if once set to FALSE, it will remain
FALSE,
Example:
a R= b;
a gets set to FALSE when b = TRUE.
Note: Notice the behaviour in case of a multiple assignment: All set and reset
assignments refer to the last member of the assignment.
Example:
a S= b R= fun1(par1,par2);
In this case b gets the reset output value of fun1, BUT: a does
not
get the set value of
b, but gets the set output value of fun1 !
Assignment as expression, extension to the IEC 61131-3 standard (ExST):
Notice that an assignment can be used as an expression.
Calling function blocks in ST
A function block (abbreviated by "FB" in the following) is called in Structured Text
according to the following syntax:
Syntax:
(FB input variable:=|, variable:=|...further FB input variables);
Example:
In the following example a timer function block (TON) is called with assignments for
the parameters IN and PT.
Then result variable Q is assigned to variable A. The timer FB is instantiated by
"TMR:TON;"
The result variable, as in IL, is addressed according to syntax .variable>:
TMR(IN := %IX5, PT := 300);
A:=TMR.Q